Sectionalizing switch



Jan. 21, 1,930.

C. A. BUTCHER SECTIONALIZING SWITCH Filed Aug. 12. 1922 i a2 1 l I 142 IWITNESSES: INVENTOR Chavles A.Bu1',che\-. v

ATTORNEY Patented Jan. 21, 1930 UNITED STATES PATENT Q-FFEE CHARLES A.BUTCHER, OF EAST PITTSBURGH, I'ENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSEELECTRIC & MANUFACTURING COMPANY, A COREORATION OF EENN- SYLVANIASECIIONALIZING SWITCH Application filed August 12, 1922. Serial No.581,319.

My invention relates to automatically reclosing circuit-controllingdevices and is particularly applicable to that type of device known as asectionalizing switch.

One object of my invention is to provide a sectionalizing switch forconnecting two sections of a system that shall connect such sectionsonly so long as current traverses the switch in a predetermineddirection.

Another object of my invention is to provide an automatically operatingsectionalizing switch that shall connect a system having a large sourceof power to a system having a small source of power, when the smallersystem is loaded to a predetermined degree, to take care of the peakloads, and that shall disconnect the two circuits when the loaddecreases and the smaller system tends to transmit energy into thelarger system.

Another object of my invention is to provide a system, of theabove-indicated character, in which the sectionalizing switch, inaddition to controlling the direction of current between the twosystems, shall be operative to connect the larger system to the smalleronly when the smaller system is free of shortcircuit conditions and theresistance of the load connected thereto exceeds a predetermined value.

In practicing my invention, I provide means that are responsive to therespective voltages of the two sections or systems and co-operatingmeans that is responsive both to the potential difference or gradientbetween the two systems and the direction of such gradient to controlthe connecting means that joins the two sections or systems.

In order to preclude the operation of the connecting means to join thetwo sections or systems while a short-circuit condition exists on thesmaller section or system, I provide means constituting a measuringcircuit to also control the connecting means.

I also provide a reverse current or energy device that operates todisconnect the two systems when the smaller tends to transmit current tothe larger system or when the direction of current between the twosections reverses.

Figure 1 of the accompanying drawing is a diagrammatic view of anelectrical system including the circuit arrangement embodying myinvention.

Fig. 2 is a schematic View of the circuit relations between variousresistors of the system, illustrating the VVheatstone bridge arrangementcomposed thereby.

Fig. 3 is a schematic view of the resistors and the relay constitutingthe measuring means in a modified arrangement.

Referring to Fig. 1, two sections or systems 1 and 2, respectively, areto be connected by a circuit-controlling device, such as asectionalizing switch 3, to permit current to be transmitted fromsection 1 to section 2. It is desired to efiect such connection onlywhen the voltage of section 1 is normal and the voltage of section 2decreases to a value that is at least some predetermined value less thanthe voltage of section 1, such, for example, as a diiierence of 100volts. If section 1 is in proper energy delivering condition and section2 is clear of short-circuits and the resistance of the connected load ismore than a predetermined value, the sectionalizing switch will beclosed.

In order to ascertain when the voltage of section 2 decreases to orbelow a predetermined value, a voltage relay &' is employed that closesits switch when the voltage of circuit 2 decreases to or below suchvalue. A similar voltage-responsive relay 5 is employed to determinewhether or not the voltage of section 1 is normal, or sufficiently nearnormal, in its value, to permit the connection of the additional load ofcircuit 2 to section 1. The relay 5 is adjusted to close its switch atapredetermined voltage of section 1 at or above which it is permissibleto connect the two sections.

In order to determine whether the potential gradient established by thepotential difference between section 1 or section 2 is in the properdirection when the predetermined potential difference between the twosections exists, a polarity relay 6, similar in operation to polarizedtelegraph relays, is connected between the sections 1 and 2 across theterminals of the sectionalizing switch 3. The polarity relay 6 closesits switch when the potential difference between the sections attains apredetermined value and is in the proper direction.

Assuming the proper condition for the operation of the three relays 4, 5and 6, namely, that the voltage of section 2 decreases to a.predetermined value, the voltage of section 1 is normal and thepotential gradient between the sections is in a predetermined directionandof a predetermined value, the voltage relay 5 will be energizedthrough the switches 4 and 6 and an interlock switch 7 controlled by thesectionalizing switch 3. The voltage" relay 5 thereupon closes itsswitch 8.

In order that section 1 may not be connected to section 2 immediatelyupon the indica tion of low voltage conditions on section 2 that may becaused by a short-ci'rcuit'on that section, a resistancesmeasuri'ngcircuit is set up as a final step tocontrol the closing of the'sectionalizing switch. Such resistance-measuring circuit comprises two.resistors 9 and 10,. respectively, connected in series between thesections 1 and 2, and an operating coil of a relay 11, that is connectedin series with a resistor 12, between the junction of the resistors 9and 10 and a. common return conductor 130i the system.

It will. be observed that, in the measuring circuit set up,,theoperating coils of the relay 11 and the resistor 12 are connected inshunt relation to the resistor 10 and a connected load 14 on the circuit2. As the resistance of the connected load varies, the potentialdifference across the resistor 10 and. the con? nected load; 14 inseries, varies, and corre-- spondingly the potential ditlerenceavailable to energize the winding ofthe, relay 11 varies.

The relay 11 thus serves, in. eliect, to measure the resistance of the.connected load 14 by the potential difi'erence across the resistor 10and the connected load. 1 1. The operation is illustrated by theschematic arrangement shown in Fig. 3. i

The sensitivity of the control relay 11 may be varied by shifting thepoint of connection of the relay 11 between the resistors 9 and 10. Byemploying a resistor 9 having; a re-. sistance exceeding that of theresistor 10, the sensitivity of the relay device 11 may be. increased inthe arrangementthat is illustrated in Fig. 3. 7

If the resistance of the circuit including. the resistor 10 and. theconnected load 1d,

. equals or exceeds a predetermined value, the

relay 11 will be sufficiently energized to close its switch. A circuitis completed thereby to energize the operating coil of. a relay 15 whichthereupon closes its switches 16. and 17,. respectively. The switch 16'is connected in parallel relation. to the switch of the relay 11 andserves to maintain aiholding circuit for the relay 15.. Iahe. switch17,. when closed, completes the circuit of. theoperating coilot thesectionalizing, switch 3. which thereupon closes the switch to connectthe sections 1 and 2.

If the load on section 2 should now decrease to such value that thevoltage of that circuit becomes normal and tends to transmit currentback into section 1,a reverse current relay 18 closes its switch 19 toshort-circuit and deenergize the winding of the relay 15. The switches16 and 17 are thereupon opened and the" sectionalizing switch 3 isopened to disconnect the two sections 1 and '2. The reverse currentrelay 18 has a voltage winding 20 connected across the section 1 and awinding 21 connected toa portion of the section conductor which servesas a current shunt.

It will be. noted that, with the addition of the resistor 22,.shown inbroken line in Fig. 1, the arrangement composed by the resistors 9, 10,12 and 22 and the relay 11 constitutes a Wheatstone bridge of which theresistor 10 and the connected load 14. constitute one arm. Thearrangement is illustrated in Fig. 2. The relay 11 may be adjustedtooperate in response to any predetermined potential difference betweenthe points to which it is connected.

It will. be noted that, by means of the system which I have hereillustrated as embodying my invention, the two sections will beautomatically connected when the voltage of the current-supplyingsection is normal and the voltage of the current-receiving section isat, or below, a predetermined value below normal, and the potentialdifference and the potential gradient between the two sections are of apredetermined, value and in a pie determined direction. ing switch ismaintained. closed only until the conditions-in the. current-receivingsection become normal and the direction of current between the sectionsis reversed. By means of the resistance-1neasuring arrangements, theimmediate connection of the two sections is prevented if a short-circuitobtains on the current-receiving section.

Although I have specified theconnecting of two sections, the switchingapparatus which I have here illustrated is applicable to two systems,such as a large city system and a small interurban system.

Apparatus of different types may be employed and various changes maybemade in the arrangement thereof without departing from thespirit andscope of my invention, asset forth in the appended claims.

I claim as my invention:

1. In an electrical distribution system, the combination with twocircuit sections, ofan automatically reclosing sectionalizing circuitbreaker for connecting said sections, means for closing said circuitbreaker, said closing means being. controlled by means responsiveto'normal potential on one of said sections, means responsive to thereslstance ot the other Also, the sectionalizsection, and meansresponsive to the diiference in the potentials of said sections.

2. In an electrical distribution system, the combination with twoadjacent circuit sections,of a sectionalizingswitch for connecting saidsections, a closing coil therefor, a relay for connecting said coil to asource of current, said relay being controlled by means responsive to anenergy-delivering condition of a predetermined one'of said sectionsrelative to the other section, and means for measuring the resistance ofthe other section.

3. I11 an electrical distribution system, the combination with twoadjacent circuit sections, of a circuit breaker for connecting saidsections, an actuating coil for said breaker, a relay for controllingsaid coil, said relay being controlled by means responsive to anenergy-deliverying condition of a predetermined one of said sectionsrelative to the other section, and means responsive to the resistance ofthe other section, and means responsive to current flow to saidfirst-mentioned section from the other section for opening said circuitbreaker.

4. In a distribution system, the combination with two adjacent circuitsections of a circuit breaker for connecting said sections, means forcontrolling the operation of said circuit breaker including meansresponsive to a voltage on one of said sections in excess of that on theother section, means responsive to the resistance of the latter, andindependent means responsive to the voltages of said sections.

5. In a distribution system, the combination with two adjacent circuitsections, of a circuit breaker for connecting said sections, andautomatic means for controlling said circuit breaker including meansresponsive to the direction of the potential gradient between saidsections, means responsive to the resistance of one of said sections,and means responsive to the voltages of said sections.

6. In an electrical system, the combination with two circuit sectionsand connecting means therefor having an operating coil, of means forcontrolling the energization of the operating coil including resistancemeans connected between the two sections, a relay responsive to thepotential drop across the resistance means, a relay responsive to the direction of the potential gradient between said circuits, and meansresponsive to the respective voltages of each circuit section.

7 In a distribution system, two circuit sections adapted to be connectedby a circuit breaker, a closing coil for said breaker and means forcontrolling said coil including relays responsive to the voltages ofsaid sections, to the direction of the voltage gradient therebetween andmeans responsive to the resistance of one of said sections.

8. In an electrical system, the combination with two adjacent circuitsections, of switching apparatus for connecting the two sections, anoperating coil therefor, and means for controlling the operating coilincluding means responsive to the direction of the potential differencebetween the two sections, and a Wheatstone bridge for measuring theresistance of the load connected to one of the sections.

9. In an electrical system, the combination with two adjacent circuitsections, of means for connecting the two sections, an operating coiltherefor, an auxiliary switch that closes when the connecting means isin open position, a resistor between the circuit sections to limit thetransfer of current therebetween when the connecting means is in openposition, a relay device connected between predetermined points of theresistor to be energized by the potential drop therebetween, and asecond relay adapted to be connected to one section and controlled bythe auxiliary switch of the connecting means, and a relay responsive tothe direction of the potential gradient between said sections, saidrelays co-operating to control the energization of the operating coil ofthe connecting means.

10. In an electrical system, the combination with two adjacent circuitsections, of switching apparatus for connecting the two sectionscomprising an electromagnetic contactor provided with an operating coil,selfresetting means responsive to predetermined current conditions inthe sections for rendering the operating coil ineffective, a resistorbetween the sections to limit the transfer of current after thecontactor opens, means responsive to the voltages of said sections andthe voltage gradient between the sections, and a relay adapted therebyto be connected be tween predetermined points of said resistor, tocontrol said operating coil in accordance with the resistance of one ofsaid sections.

In testimony whereof, I have hereunto subscribed my name this 5th day ofAugust, 1922.

CHARLES A. BUTCHER.

